The present invention pertains to a method of producing blanks from a coiled ribbon of sheet material and blanks produced thereby, and more particularly, to blanks for sheet material forming processes and a method of producing the same from coiled ribbons of sheet material in which scrap is minimized.
Sheet metal forming processes have long been used and range from drawing, bending, straightening, stretching, shearing, punching, piercing, extruding, notching, parting, nibbling, perforating, dimpling, corrugating, curling, wiring, hemming, seaming, bulging, necking, swaging, spinning, coining, embossing, ironing, flanging, stretch forming, juggling, slitting, shaving, lancing, trimming, slotting, and combinations thereof. Many complex parts from sheet metal are formed of different sizes including auto body parts such as fenders, trunk lids, and hoods, appliance bodies such as refrigerator shells, range and dishwasher bodies and the like. The largest practical blanks from sheet or coiled steel are used in the automotive industry for floors and roofs of automobiles. The smallest blanks are generally used in the precious metal industry for electrical contact tips, these blanks being almost microscopic in size. Similar processes are now being used with other deformable materials such as plastics and composites.
In performing each of these operations and forming blanks for each of these parts, the minimization of scrap is always desirable. However, it is well known to those familiar with such operations that the tooling requires the application of a technology which is only limited by the composition of the material and its physical properties. In each of the operations there are limitations beyond which the material cannot be formed without splitting, cracking or otherwise stretching the material beyond its limits by which failure of the part is assured.
Essential in all forming processes is the production of a blank having a part portion surrounded by a scrap portion. The scrap portion must be significantly large in order for the blank to be grasped firmly in the tooling between the upper binder and the lower binder during the forming process. This scrap portion must be large enough to insure a firm grip and yet allow the part to be formed without failure of the part beginning in the scrap portion of the blank. While lock beads, gripper beads, other material flow restrictions, or other discontinuities in the scrap portion may tend to insure the necessary grip and to minimize scrap, there is always a necessity for good blank design and blank layout on a ribbon of coiled sheet material from which the blanks are formed.
While it is known in other art in the textile industry and the like to design blanks in a manner to efficiently utilize sheet material (see, for example, U.S. Pat. No. 2,335,292 issued to Messenger on Nov. 30, 1943) these techniques have not been utilized in the sheet metal forming industry, as many such techniques do not allow for the necessary scrap portion of the blank required by the forming process, and that it has been experienced and thought in the past that any discontinuous boundary could be the site for splits resulting from metal stretching during the forming process. While these blank designs do conserve material, blank designs previously used on textiles and paper, cardboard, plasterboard, etc. , have not been deemed applicable to the sheet material forming industry and its processes. In fact, the sheet material forming industry has discarded the notion and taught away from use of such blanks having a discontinuous boundary portion for all of the above reasons.
In this context, it is therefore highly desirable to provide a new and novel blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material.
It is also highly desirable to provide a new and novel blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material which minimizes scrap and maximizes the number of blanks formed from the sheet material.
It is also highly desirable to provide a new and novel blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material which has at least one boundary portion which is discontinuous.
It is also highly desirable to provide a new and novel blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material in which at least one portion of the peripheral scrap portion of the blank is shared with adjacent blanks.
It is also highly desirable to provide a new and novel Blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material in which at least two boundaries are discontinuous.
It is also highly desirable to provide a new and novel blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material in which at least two peripheral scrap portions of the blank are shared with adjacent blanks.
It is also highly desirable to provide a new and novel blank for a sheet material forming process and a plurality of blanks for a sheet material forming process arranged on a roll of sheet material and a method of producing a plurality of blanks from a coiled ribbon of sheet material which includes all of the above desired features.